Resonant excitation of twisted spin waves in magnetic vortices using rotating magnetic fields

TL;DR

This paper demonstrates through micromagnetic simulations and analytical derivations that twisted spin waves with controllable topological charge naturally exist in thick ferromagnetic disks and can be excited using rotating magnetic fields.

Contribution

It provides the first demonstration of natural twisted spin wave modes in thick ferromagnetic disks and shows how to excite and control them with rotating magnetic fields.

Findings

Twisted spin waves naturally exist in thick ferromagnetic disks.

Rotating magnetic fields can excite these modes at their eigenfrequencies.

The topological charge of twisted spin waves can be controlled by the excitation field.

Abstract

Twisted spin waves attracted research attentions lately and the orbital angular momentum they carry may be utilized in communication and computing technologies. In this work, we manifest by micromagnetic simulations that twisted spin wave modes naturally exist in thick ferromagnetic disks. The twisted spin waves can be readily stimulated using rotating magnetic field when it is tuned to the eigenfrequency of corresponding modes. We analytically derive dispersion relation of the twisted spin waves and the results agree well with the numerical studies. Lastly, we demonstrate that the topological charge of twisted spin waves can be controlled by the exciting field.